CN105607131A - Method and apparatus for obtaining full-region apparent resistivity spectrum of ground by using coding source electromagnetic sounding method - Google Patents

Abstract

The invention provides a method and apparatus for obtaining a full-region apparent resistivity spectrum of a ground by using a coding source electromagnetic sounding method. The method comprises: a current signal is inputted into a to-be-measured ground and an electromagnetic field response signal time sequence outputted by the to-be-measured ground is collected, wherein the current signal is an inverse repeated M sequence and the period of the signal is an even multiple number of a power frequency period; according to the current signal and the electromagnetic field response signal time sequence, a frequency response of the to-be-measured ground is obtained by means of cyclic cross correlation; and on the basis of the frequency response of the to-be-measured ground and a received electromagnetic field component, a full-region apparent resistivity spectrum of the to-be-measured ground is obtained. According to the invention, on the basis of current signal excitation of the inverse repeated M sequence, the full-region apparent resistivity spectrum is obtained by using the cyclic cross-correlation technology, so that the efficiency of obtaining the full-region apparent resistivity is improved and the frequency resolution of the obtained full-region apparent resistivity is enhanced. Moreover, because the cross-correlation method is employed and the inverse repeated M sequence period of the current signal is an even multiple number of the power frequency period, the power frequency interference can be effectively suppressed and the anti-interference capability is enhanced.

Description

Coding source electromagnetic sounding method is obtained method and the device of the earth APPARENT RESISTIVITY spectrum

Technical field

The present invention relates to signals collecting and process field, System Discrimination field and geophysical electricity magnetic sounding exploration neckTerritory, obtains in particular to a kind of coding source electromagnetic sounding method method and the device that the earth APPARENT RESISTIVITY is composed.

Background technology

Due to the electromagnetic field of the different frequency skin depth difference in the earth, therefore in electromagnetic sounding field, can lead toCross and measure electromagnetic field component on earth's surface, obtain the APPARENT RESISTIVITY of the earth to be measured, the change according to APPARENT RESISTIVITY with frequencyChange, infer the electrical depth profile situation of the earth to be measured.

Current, in correlation technique, conventionally adopt frequency sweep method to obtain the apparent resistivity of the earth to be measured. In the time of application frequency sweep method,Set in advance multiple different frequencies, in the time of exploration, believe to the electric current of the default multiple different frequencies of the earth input to be measured successivelyNumber, according to the earth to be measured, electromagnetic response output signal corresponding to the current signal of multiple different frequencies to be observed, acquisition is treatedSurvey the apparent resistivity of the earth.

Due to the current signal of multiple different frequencies of presetting to the earth input to be measured successively, frequency of a frequency like thisRate carry out frequency sweep exploration, efficiency is very low, and does not adopt Correlation Identification technology, antijamming capability is very low.

Summary of the invention

In view of this, the object of the embodiment of the present invention is to provide a kind of coding source electromagnetic sounding method to obtain the earth whole district to lookThe method of resistivity spectrum and device, improved the efficiency of obtaining APPARENT RESISTIVITY, and improved the APPARENT RESISTIVITY of obtainingFrequency resolution, and can effectively suppress power frequency disturb, strengthened antijamming capability.

First aspect, the embodiment of the present invention provides a kind of coding source electromagnetic sounding method to obtain the earth APPARENT RESISTIVITY spectrumMethod, described method comprises:

To the earth input current signal to be measured, gather the electromagnetic field response signal time series of described the earth output to be measured,Described current signal is against repeating the even-multiple that M sequence and cycle are power frequency period;

According to described current signal and described electromagnetic field response signal time series, obtain institute by Cyclic Cross-Correlation Transform modeState the frequency response of the earth to be measured;

According to the frequency response of described the earth to be measured and reception electromagnetic field component, electricity is looked by the whole district that obtains described the earth to be measuredResistance rate spectrum.

In conjunction with first aspect, the embodiment of the present invention provides the implementation that the first of above-mentioned first aspect is possible, itsIn,

Described according to described current signal and described electromagnetic field response signal time series, obtain by Cyclic Cross-Correlation Transform modeThe frequency response of getting described the earth to be measured, comprising:

Trigger software program generating reference signal according to the time series cycle of described current signal and sample rate, described in inciting somebody to actionElectromagnetic field response signal time series and described current signal carry out Cyclic Cross-Correlation Transform with described reference signal respectively, described in obtainingThe cross-correlation time series that the cross-correlation time series that electromagnetic field response signal time series is corresponding and described current signal are corresponding;

Cross-correlation time series and the described current signal corresponding to described electromagnetic field response signal time series are correspondingCross-correlation time series is carried out respectively FFT, obtains described electromagnetic field response signal seasonal effect in time series crosspower spectrumAnd the crosspower spectrum of described current signal;

According to the crosspower spectrum of described electromagnetic field response signal seasonal effect in time series crosspower spectrum and described current signal, obtainThe frequency response of described the earth to be measured.

In conjunction with first aspect, the embodiment of the present invention provides the second of above-mentioned first aspect possible implementation, itsIn,

Described reception electromagnetic field component is horizontal component of electric field time series;

Described according to the frequency response of described the earth to be measured and reception electromagnetic field component, obtain the whole district of described the earth to be measuredApparent resistivity spectrum, comprising:

According to the frequency response of described the earth to be measured, obtain impedance spectrum and the reception of described the earth to be measured by formula (1)The relational expression of electromagnetic field component and ground resistivity;

Relational expression corresponding to impedance spectrum to described the earth to be measured corresponding to formula (1) is out of shape, and obtains formula (2) instituteThe APPARENT RESISTIVITY spectrum of the described the earth to be measured showing;

$Z_{Ex}\left(\mathrm{\ω}\right)=\frac{\mathrm{\ρ}\left(\mathrm{\ω}\right)dL\·MN}{2{\mathrm{\πr}}^3}{C}_{Ex}\mathrm{...}\left(1\right)$

${\mathrm{\ρ}}_{Ex}\left(\mathrm{\ω}\right)=\frac{2{\mathrm{\πr}}^3\·Z_{Ex}\left(\mathrm{\ω}\right)}{dL\·MN\·C_{Ex}}\mathrm{...}\left(2\right)$

Wherein, in formula (1) and (2), Z_Ex(ω) be the earth impedance, ρ is even resistivity greatly, and ω is frequency,DL is two die openings of horizontal electric dipole, the electrode spacing that MN is collecting electrode, the mid point that r is collecting electrode and horizontal electric dipoleThe two poles of the earth mid point between distance,For the mid point of collecting electrode extremelyThe angle of the line between the two poles of the earth mid point of horizontal electric dipole and the two poles of the earth line of horizontal electric dipole, i is imaginary unit,For even wave number greatly, μ₀For the magnetic conductivity of free space, ρ_Ex(ω) be described APPARENT RESISTIVITY.

In conjunction with first aspect, the embodiment of the present invention provides the third possible implementation of above-mentioned first aspect, itsIn,

Described reception electromagnetic field component is vertical magnetic field time series;

Described according to the frequency response of described the earth to be measured and reception electromagnetic field component, obtain the whole district of described the earth to be measuredApparent resistivity spectrum, comprising:

According to the frequency response of described the earth to be measured, obtain the frequency response of described the earth to be measured and connect by formula (3)Receive the relational expression of electromagnetic field component and ground resistivity;

Relational expression corresponding to described frequency response that formula (3) is corresponding is out of shape, obtain shown in formula (4) described inThe APPARENT RESISTIVITY spectrum of the earth to be measured;

Wherein, in formula (3) and (4), Z_Hz(ω) be described frequency response, ρ is even resistivity greatly, and ω is frequentlyRate, two die openings that dL is horizontal electric dipole, the distance between the two poles of the earth mid point of the mid point that r is collecting electrode and horizontal electric dipoleFrom, μ₀For the magnetic conductivity of free space, i is imaginary unit,For the mid point of collecting electrode to the two poles of the earth mid point of horizontal electric dipole itBetween line and the angle of the two poles of the earth line of horizontal electric dipole, $C_{Hz}=1-(1-{\mathrm{ik}}_{1}r-\frac{1}{3}{\left(k_{1}r\right)}^2)\exp \left({\mathrm{ik}}_{1}r\right),k_1^2={\mathrm{i\ω\μ}}_0/\mathrm{\ρ}$ For even wave number greatly, ρ_Hz(ω) be described APPARENT RESISTIVITY.

In conjunction with first aspect, the embodiment of the present invention provides the 4th kind of possible implementation of above-mentioned first aspect, itsIn, described method also comprises:

According to the frequency response of described the earth to be measured, obtain the transfer function of described the earth to be measured, by described transfer functionCalculate step response or the impulse response of described the earth to be measured, according to described step response late period asymptotic value or described impulse ringIn the peak value moment of answering, calculate the apparent resistivity of described the earth to be measured.

Second aspect, the embodiment of the present invention provides a kind of coding source electromagnetic sounding method to obtain the earth APPARENT RESISTIVITY spectrumDevice, described device comprises:

Acquisition module, for to the earth input current signal to be measured, gathers the electromagnetic field response of described the earth output to be measuredSignal time sequence, described current signal is against repeating the even-multiple that M sequence and cycle are power frequency period;

The first acquisition module, for according to described current signal and described electromagnetic field response signal time series, by followingThe frequency response that ring cross-correlation mode is obtained described the earth to be measured;

The second acquisition module, for according to the frequency response of described the earth to be measured and receive electromagnetic field component, described in obtainingThe APPARENT RESISTIVITY spectrum of the earth to be measured.

In conjunction with second aspect, the embodiment of the present invention provides the implementation that the first of above-mentioned second aspect is possible, itsIn,

Described the first acquisition module comprises:

Cyclic Cross-Correlation Transform unit, for the time series cycle according to described current signal and sample rate triggering software programGenerating reference signal, carries out described electromagnetic field response signal time series and described current signal respectively with described reference signalCyclic Cross-Correlation Transform, obtains described electromagnetic field response signal time series corresponding cross-correlation time series and described current signal pairThe cross-correlation time series of answering;

Fourier transformation unit, for to cross-correlation time series corresponding to described electromagnetic field response signal time series andThe cross-correlation time series that described current signal is corresponding is carried out respectively FFT, obtains described electromagnetic field response signalThe crosspower spectrum of seasonal effect in time series crosspower spectrum and described current signal;

Acquiring unit, for according to described electromagnetic field response signal seasonal effect in time series crosspower spectrum and described current signalCrosspower spectrum, the frequency response of obtaining described the earth to be measured.

In conjunction with second aspect, the embodiment of the present invention provides the second of above-mentioned second aspect possible implementation, itsIn,

Described reception electromagnetic field component is horizontal component of electric field time series;

Described the second acquisition module comprises:

First obtains unit, for according to the frequency response of described the earth to be measured, obtains described to be measured large by formula (1)The impedance spectrum on ground and the relational expression that receives electromagnetic field component and ground resistivity;

The first computing unit, for carrying out the relational expression corresponding to impedance spectrum of described the earth to be measured corresponding to formula (1)Distortion, the APPARENT RESISTIVITY that obtains the described the earth to be measured shown in formula (2) is composed;

$Z_{Ex}\left(\mathrm{\ω}\right)=\frac{\mathrm{\ρ}\left(\mathrm{\ω}\right)dL\·MN}{2{\mathrm{\πr}}^3}{C}_{Ex}\mathrm{...}\left(1\right)$

${\mathrm{\ρ}}_{Ex}\left(\mathrm{\ω}\right)=\frac{2{\mathrm{\πr}}^3\·Z_{Ex}\left(\mathrm{\ω}\right)}{dL\·MN\·C_{Ex}}\mathrm{...}\left(2\right)$

Wherein, in formula (1) and (2), Z_Ex(ω) be the earth impedance, ρ is even resistivity greatly, and ω is frequency,DL is two die openings of horizontal electric dipole, the electrode spacing that MN is collecting electrode, the mid point that r is collecting electrode and horizontal electric dipoleThe two poles of the earth mid point between distance,For the mid point of collecting electrode extremelyThe angle of the line between the two poles of the earth mid point of horizontal electric dipole and the two poles of the earth line of horizontal electric dipole, i is imaginary unit,For even wave number greatly, μ₀For the magnetic conductivity of free space, ρ_Ex(ω) be described APPARENT RESISTIVITY.

In conjunction with second aspect, the embodiment of the present invention provides the third possible implementation of above-mentioned second aspect, itsIn,

Described reception electromagnetic field component is vertical magnetic field time series;

Described the second acquisition module comprises:

Second obtains unit, for according to the frequency response of described the earth to be measured, obtains described to be measured large by formula (3)The frequency response on ground and the relational expression that receives electromagnetic field component and ground resistivity;

The second computing unit, for relational expression corresponding to described frequency response corresponding to formula (3) is out of shape, obtainsThe APPARENT RESISTIVITY spectrum of the described the earth to be measured shown in formula (4);

Wherein, in formula (3) and (4), Z_Hz(ω) be described frequency response, ρ is even resistivity greatly, and ω is frequentlyRate, two die openings that dL is horizontal electric dipole, the distance between the two poles of the earth mid point of the mid point that r is collecting electrode and horizontal electric dipoleFrom, μ₀For the magnetic conductivity of free space, i is imaginary unit,For the mid point of collecting electrode to the two poles of the earth mid point of horizontal electric dipole itBetween line and the angle of the two poles of the earth line of horizontal electric dipole, $C_{Hz}=1-(1-{\mathrm{ik}}_{1}r-\frac{1}{3}{\left(k_{1}r\right)}^2)\exp \left({\mathrm{ik}}_{1}r\right),k_1^2={\mathrm{i\ω\μ}}_0/\mathrm{\ρ}$ For even wave number greatly, ρ_Hz(ω) be described APPARENT RESISTIVITY.

In conjunction with second aspect, the embodiment of the present invention provides the 4th kind of possible implementation of above-mentioned second aspect, itsIn, described device also comprises:

Computing module, for according to the frequency response of described the earth to be measured, obtains the transfer function of described the earth to be measured, byDescribed transfer function is calculated step response or the impulse response of described the earth to be measured, according to the asymptotic value in late period of described step responseOr the peak value moment of described impulse response, calculate the apparent resistivity of described the earth to be measured.

In the method providing in the embodiment of the present invention and device, to the earth input current signal to be measured, gather the earth to be measuredThe electromagnetic field response signal time series of output, current signal is against repeating the even-multiple that M sequence and cycle are power frequency period; RootAccording to current signal and electromagnetic field response signal time series, the frequency response of obtaining the earth to be measured by Cyclic Cross-Correlation Transform mode;According to the frequency response of the earth to be measured and reception electromagnetic field component, obtain the APPARENT RESISTIVITY spectrum of the earth to be measured. The present invention is logicalThe current signal of crossing the contrary M of repetition sequence excites, and adopts Cyclic Cross-Correlation Transform technology to obtain APPARENT RESISTIVITY spectrum, has improved and has obtained entirelyThe efficiency of district's apparent resistivity, and improved the frequency resolution of the APPARENT RESISTIVITY of obtaining, and due to adopt cross-correlation method andThe even-multiple that the contrary cycle that repeats M sequence of current signal is power frequency period, can effectively suppress power frequency and disturb, and has strengthened anti-interference energyPower.

For above-mentioned purpose of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly, and coordinateAppended accompanying drawing, is described in detail below.

Brief description of the drawings

In order to be illustrated more clearly in the technical scheme of the embodiment of the present invention, attached by required use in embodiment belowFigure is briefly described, and should be appreciated that the following drawings only shows some embodiment of the present invention, and it is right therefore should not to be counted asThe restriction of scope, for those of ordinary skill in the art, is not paying under the prerequisite of creative work, can also be according to thisA little accompanying drawings obtain other relevant accompanying drawings.

Figure 1A shows a kind of method flow diagram that obtains APPARENT RESISTIVITY that the embodiment of the present invention 1 provides;

Figure 1B shows a kind of time-domain waveform schematic diagram against repeating M sequence that the embodiment of the present invention 1 provides;

Fig. 1 C shows a kind of power spectrum schematic diagram against repeating M sequence that the embodiment of the present invention 1 provides;

Fig. 1 D shows the signal of the auto-correlation function curve of a kind of contrary M of the repetition sequence that the embodiment of the present invention 1 providesFigure;

Signal is arranged in a kind of coding source electromagnetic sounding array work that Fig. 1 E shows the embodiment of the present invention 1 to be providedFigure;

Fig. 1 F shows the structural representation of a kind of coding source electromagnetic sounding emission system that the embodiment of the present invention 1 providesFigure;

Fig. 1 G shows the structural representation of a kind of coding source electromagnetic sounding receiver system that the embodiment of the present invention 1 providesFigure;

Fig. 2 shows a kind of apparatus structure schematic diagram that obtains APPARENT RESISTIVITY that the embodiment of the present invention 2 provides.

Detailed description of the invention

Below in conjunction with accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, completeGround is described, and obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiment. Conventionally existThe assembly of the embodiment of the present invention of herein describing in accompanying drawing and illustrate can be arranged and design with various configuration. CauseThis, below the detailed description of the embodiments of the invention that provide in the accompanying drawings is not intended to limit claimed of the present inventionScope, but only represent selected embodiment of the present invention. Based on embodiments of the invention, those skilled in the art are not doingGo out the every other embodiment obtaining under the prerequisite of creative work, all belong to the scope of protection of the invention.

Consider the current signal of multiple different frequencies of presetting to the earth input to be measured successively in correlation technique, like this oneA frequency of individual frequency carry out frequency sweep exploration, efficiency is very low, and does not adopt Correlation Identification technology, antijamming capability is not strong.Based on this, the embodiment of the present invention provides a kind of coding source electromagnetic sounding method to obtain method and the dress of the earth APPARENT RESISTIVITY spectrumPut. Be described below by embodiment.

Embodiment 1

Referring to Figure 1A, the embodiment of the present invention provides a kind of coding source electromagnetic sounding method to obtain the earth APPARENT RESISTIVITY spectrumMethod. The method specifically comprises the following steps:

Step 101: to the earth input current signal to be measured, gather the electromagnetic field response signal time order of the earth output to be measuredRow, current signal is against repeating the even-multiple that M sequence and cycle are power frequency period.

In the embodiment of the present invention, trigger linear feedback shift register by clock signal and generate current signal, this electric currentSignal is the periodically pseudorandom contrary M of repetition sequence.

The executive agent of the embodiment of the present invention is to obtain the earth APPARENT RESISTIVITY spectrum for coding source electromagnetic sounding methodDevice, is provided with N+1 bit register in this device, N is more than or equal to 3 integer. In this N+1 bit register, deposit for 1Device is used for generating two divided-frequency shift register clock signal, remaining N bit register composition linear feedback shift register, in advanceThe feedback bit of setting linear feedback shift register, this N bit linear feedback shift register has formed maximum length pseudorandom m orderRow produce circuit. Above-mentioned another 1 bit register two divided-frequency linear feedback shift register clock signal, by this clock signal and N positionThe pseudorandom m sequence that linear feedback shift register generates is carried out XOR, and realization, obtains every position negate pseudorandom m sequenceTo the contrary M sequence that repeats. Drive high-power IGBT (InsulatedGateBipolarTransistor, insulated gate bipolar crystalline substanceBody pipe) inverter, feed code current by HORIZONTAL ELECTRIC DIPOLE to the earth. With receiving the identical receiver of electromagnetic field, according toThe sample rate of setting is time series by the code current signal sampling of input the earth, and the time series signal that sampling is obtained is trueBe decided to be current signal, current signal is multiply periodic signal.

Wherein, contrary cycle and the frequency band that repeats M sequence is adjustable, can be by selecting different linear feedback shiftsThe timely clock frequency of register figure place regulates. The figure place of linear feedback shift register is generally got 5,6,7,8,9 or 10, clockFrequency can be selected in frequency separation [0.5Hz, 10kHz]. Wherein, as shown in table 1, different linear feedback shifts are postedStorage figure place and clock frequency, corresponding contrary cycle and the long difference of sequence bit that repeats M sequence. In table 1, primitive polynomial is for producingThe raw contrary feedback bit expression formula that repeats M sequence, clock frequency is just schematically given with the contrary corresponding table that repeats M sequence periodGo out clock frequency, in concrete operations, clock frequency can be selected in frequency separation [0.5Hz, 10kHz]. Change generation contraryThe clock frequency that repeats M sequence, can realize easily frequency-division section and excite, and generally just excites for 2-3 time and can obtain 0.1Hz extremelyThe frequency coverage of the frequency range of 10000Hz, has improved operating efficiency.

Table 1

Wherein, the contrary cycle that repeats M sequence is 2 times of cycle of maximum linear feedback pseudorandom m sequence. Get the contrary M of repetitionThe cycle of sequence is the even-multiple of power frequency period, i.e. the cycle of the current signal even-multiple that is power frequency period. At commercial powerUnder many scenes, current signal can be subject to the impact of commercial power. And that the correlation peak of current signal shows as is periodically positive and negativeAlternately occur, therefore the cycle of the obtaining current signal even-multiple that is power frequency period, can effectively suppress power frequency and disturb, and weakens workFrequently disturb the impact on current signal, and then improve the accuracy of the frequency response function obtaining.

Wherein, as shown in Figure 1B, in contrary repetition M 1 cycle of sequence, waveform is random to the time-domain waveform of contrary repetition M sequence. As shown in Figure 1 C, its power spectrum is discrete line spectrum to the power spectrum of contrary repetition M sequence. The contrary auto-correlation letter that repeats M sequenceNumber curve is as shown in Fig. 1 D, and the curve of this auto-correlation function shows as the positive and negative spike replacing.

In coding source electromagnetic sounding array work arrangement as shown in Fig. 1 E, by horizontal electric dipole source AB toThe contrary current signal that repeats M sequence of the earth input to be measured, and gather by collecting electrode MN or bar magnet the electricity that the earth to be measured is exportedMagnetic responsiveness signal time sequence. In embodiments of the present invention, both can the method for synchronization gather electromagnetic field response signal time orderRow, also can asynchronous system gather electromagnetic field response signal time series.

Step 102: according to current signal and electromagnetic field response signal time series, obtain and treat by Cyclic Cross-Correlation Transform modeSurvey the frequency response of the earth.

Trigger software program generating reference signal according to the time series cycle of current signal and sample rate, electromagnetic field is rungInduction signal time series and current signal carry out Cyclic Cross-Correlation Transform with reference signal respectively, obtain electromagnetic field response signal time orderBe listed as the cross-correlation time series that corresponding cross-correlation time series and current signal are corresponding.

Wherein, this reference signal sequence length is long with the electromagnetic field response signal and the input current signal sequence that participate in calculatingSpending identically, is the integral multiple in input current signal cycle. The generating mode of this reference signal can with the generation side of current signalFormula is identical, also can from the time series of current signal, extract. Wherein, the linear feedback shift that produces the contrary M of repetition sequence is setAfter the figure place and feedback bit of register, the contrary M sequence that repeats of generation is fixed, and is that different dwell vessel original states producesRaw contrary repetition has time delay between M sequence, but the spectrum distribution of the contrary M of the repetition sequence producing is identical.

Wherein, the cycle of this reference signal is identical with the current signal cycle, is the even-multiple of power frequency period. Follow-up basisThis reference signal is carried out Cyclic Cross-Correlation Transform processing to current signal and electromagnetic field response signal, can effectively suppress power frequency and doDisturb, improve antijamming capability.

In embodiments of the present invention, according to above-mentioned reference signal and current signal, by following formula (5) with reference to signalCarry out Cyclic Cross-Correlation Transform with current signal, obtain the cross-correlation time series that current signal is corresponding. And, according to reference signal andElectromagnetic field response signal time series, carries out with reference to signal and electromagnetic field response signal time series by following formula (6)Cyclic Cross-Correlation Transform, obtains cross-correlation time series corresponding to electromagnetic field response signal time series.

C_us(t)＝cxcorr(u,SS)…(5)

C_ys(t)＝cxcorr(yout,SS)…(6)

Wherein, in formula (5) and (6), u is current signal, and yout is electromagnetic field response signal time series, and SS is ginsengExamine signal, t is the time, C_us(t) be the cross-correlation time series that current signal is corresponding, C_ys(t) be the electromagnetic field response signal timeThe cross-correlation time series that sequence is corresponding, cxcorr (u, SS) represents current signal u and reference signal SS to circulate mutuallyClose computing, cxcorr (yout, SS) represents electromagnetic field response signal time series yout and reference signal SS to circulate mutuallyRelated operation.

Obtain by the way electromagnetic field response signal time series corresponding cross-correlation time series and current signalAfter corresponding cross-correlation time series, cross-correlation time series and the current signal corresponding to electromagnetic field response signal time seriesCorresponding cross-correlation time series is carried out respectively FFT, obtains electromagnetic field response signal seasonal effect in time series cross-powerThe crosspower spectrum of spectrum and current signal.

Particularly, by following formula (7), cross-correlation time series corresponding to current signal carried out to fast Flourier changeChange, obtain the crosspower spectrum of current signal. And by following formula (8) to electromagnetic field response signal time series corresponding mutuallyTime related sequence carries out FFT, obtains electromagnetic field response signal seasonal effect in time series crosspower spectrum.

$P_{C_{us}}\left(\mathrm{\ω}\right)=FFT\left(L_{us}\right(t\left)\right)\mathrm{...}\left(7\right)$

$P_{C_{ys}}\left(\mathrm{\ω}\right)=FFT\left(L_{ys}\right(t\left)\right)\mathrm{...}\left(8\right)$

Wherein, in formula (7) and (8), ω is frequency,For the crosspower spectrum of current signal,For electromagnetismField response signal seasonal effect in time series crosspower spectrum, FFT (C_us(t)) represent the cross-correlation time series C corresponding to current signal_us(t) carry out FFT, FFT (C_ys(t)) represent the cross-correlation time corresponding to electromagnetic field response signal time seriesSequence C_ys(t) carry out FFT.

Obtain by the way the crosspower spectrum of electromagnetic field response signal seasonal effect in time series crosspower spectrum and current signalAfter, the ratio between electromagnetic field response signal seasonal effect in time series crosspower spectrum and the crosspower spectrum of current signal of calculating same frequencyValue, obtains the frequency response of the earth to be measured as shown in formula (9).

$H\left(\mathrm{\ω}\right)=\frac{P_{C_{ys}}\left(\mathrm{\ω}\right)}{P_{C_{us}}\left(\mathrm{\ω}\right)}\mathrm{...}\left(9\right)$

Wherein, in formula (9), ω is frequency values,For electromagnetic field response signal time corresponding to frequency values ωThe spectral line peak value of sequence,For the spectral line peak value of current signal corresponding to frequency values ω, the frequency that H (ω) is the earth to be measuredResponse.

In the embodiment of the present invention, in the time adopting the method for synchronization to gather current signal and electromagnetic field response signal seasonal effect in time seriesBetween when sequence, also, according to the crosspower spectrum of electromagnetic field response signal seasonal effect in time series crosspower spectrum and current signal, obtain to be measuredThe phase spectrum of the earth, the phase spectrum of the earth to be measured is as shown in formula (10).

Wherein, in formula (10), mod is modulus operator,During for electromagnetic field response signal corresponding to frequencies omegaBetween the phase place of crosspower spectrum of sequence,For the phase place of the crosspower spectrum of current signal corresponding to frequencies omega,For treatingSurvey phase spectrum corresponding to the earth.

In addition, if while adopting asynchronous system to gather current signal and electromagnetic field response signal seasonal effect in time series time series,The amplitude spectrum of the earth to be measured can only be obtained, phase spectrum cannot be obtained.

Step 103: according to the frequency response of the earth to be measured and reception electromagnetic field component, electricity is looked by the whole district that obtains the earth to be measuredResistance rate spectrum.

In embodiments of the present invention, receiving electromagnetic field component can be horizontal component of electric field time series or vertical magnetic field time orderRow, horizontal component of electric field time series represents with symbol Ex, vertical magnetic field time series represents with symbol Hz. When receiving electromagnetic field componentWhen different, obtain the also difference of mode of the APPARENT RESISTIVITY spectrum of the earth to be measured.

In the time that reception electromagnetic field component is horizontal component of electric field time series, the whole district that obtains in the following way the earth to be measured looksResistivity spectrum, specifically comprises:

According to the frequency response of the earth to be measured, obtain the impedance spectrum and reception electromagnetism of described the earth to be measured by formula (1)The relational expression of field component and ground resistivity; Relational expression corresponding to impedance spectrum to described the earth to be measured corresponding to formula (1) enteredRow distortion, the APPARENT RESISTIVITY that obtains the described the earth to be measured shown in formula (2) is composed;

$Z_{Ex}\left(\mathrm{\ω}\right)=\frac{\mathrm{\ρ}\left(\mathrm{\ω}\right)dL\·MN}{2{\mathrm{\πr}}^3}{C}_{Ex}\mathrm{...}\left(1\right)$

${\mathrm{\ρ}}_{Ex}\left(\mathrm{\ω}\right)=\frac{2{\mathrm{\πr}}^3\·Z_{Ex}\left(\mathrm{\ω}\right)}{dL\·MN\·C_{Ex}}\mathrm{...}\left(2\right)$

Wherein, in formula (1) and (2), Z_Ex(ω) be the earth impedance, ρ is even resistivity greatly, and ω is frequency,DL is two die openings of horizontal electric dipole, the electrode spacing that MN is collecting electrode, the mid point that r is collecting electrode and horizontal electric dipoleThe two poles of the earth mid point between distance,For the mid point of collecting electrode extremelyThe angle of the line between the two poles of the earth mid point of horizontal electric dipole and the two poles of the earth line of horizontal electric dipole, i is imaginary unit,For even wave number greatly, μ₀For the magnetic conductivity of free space, ρ_Ex(ω) be APPARENT RESISTIVITY.

In above-mentioned formula (1) and (2), dL, MN, r andBe the device parameter of observation device, according to field source and observationPosition coordinate is determined these parameters, is observing after horizontal component of electric field time series, according to the frequency response of the earth to be measured, level electricityField time sequence and these device parameters, the APPARENT RESISTIVITY that obtains the earth to be measured by formula (1) and (2) is composed.

In embodiments of the present invention, in the time that reception electromagnetic field component is horizontal component of electric field time series Ex, observation is to receiveInterelectrode magnitude of voltage time series, this magnitude of voltage time series V_Ex＝E_xMN, the electrode spacing that MN is collecting electrode, soBy above computational process, the frequency response deformable shown in formula (9) is following formula (11):

$Z_{Ex}\left(\mathrm{\ω}\right)=\frac{P_{{\mathrm{CV}}_{ex}s}\left(\mathrm{\ω}\right)}{P_{{\mathrm{CI}}_{AB}s}\left(\mathrm{\ω}\right)}\mathrm{...}\left(11\right)$

Wherein, in formula (11),For reference signal SS and magnitude of voltage time series V_ExCrosspower spectrum,For the current signal I of the two-stage transmitting of reference signal SS and horizontal electric dipole_AB(t) crosspower spectrum.

The computing formula (12) of the electric field Ex being produced by even Earth Surface horizontal electric dipole source:

Wherein, in formula (12), ρ is even large resistivity, and I is emission current, r be collecting electrode mid point withDistance between the two poles of the earth mid point of horizontal electric dipole,That the mid point of collecting electrode is between the two poles of the earth mid point of horizontal electric dipoleThe angle of the two poles of the earth line of line and horizontal electric dipole, dL is two die openings of horizontal electric dipole,For evenly largeThe wave number on ground, i is imaginary unit, μ₀For the magnetic conductivity of free space.

Above-mentioned formula (12) both sides, divided by emission current I, then, with formula (11) correspondent equal, can be obtained to formula(1) the earth impedance Z of the earth to be measured shown in_Ex(ω), Z wherein_Ex(ω) be by observation electric field Ex magnitude of voltage and excitation current IThe earth impedance that Cyclic Cross-Correlation Transform identification obtains. By above-mentioned formula (1) is out of shape and can be obtained as shown in formula (2)The APPARENT RESISTIVITY spectrum of the earth to be measured, wherein the APPARENT RESISTIVITY shown in formula (2) need to adopt solution by iterative method.

In embodiments of the present invention, in the time that reception electromagnetic field component is vertical magnetic field time series Hz, in the following wayThe APPARENT RESISTIVITY spectrum of obtaining the earth to be measured, specifically comprises:

According to the frequency response of the earth to be measured, obtain the frequency response and reception electricity of described the earth to be measured by formula (3)The relational expression of magnetic-field component and ground resistivity; Relational expression corresponding to described frequency response that formula (3) is corresponding is out of shape,Obtain the APPARENT RESISTIVITY spectrum of the described the earth to be measured shown in formula (4);

Wherein, in formula (3) and (4), Z_Hz(ω) be frequency response, ρ is even resistivity greatly, and ω is frequency,DL is two die openings of horizontal electric dipole, the distance between the two poles of the earth mid point of the mid point that r is collecting electrode and horizontal electric dipole, μ₀For the magnetic conductivity of free space, i is imaginary unit,For the mid point of collecting electrode is between the two poles of the earth mid point of horizontal electric dipoleThe angle of the two poles of the earth line of line and horizontal electric dipole, $C_{Hz}=1-(1-{\mathrm{ik}}_{1}r-\frac{1}{3}{\left(k_{1}r\right)}^2)\exp \left({\mathrm{ik}}_{1}r\right),k_1^2={\mathrm{i\ω\μ}}_0/\mathrm{\ρ}$ For even wave number greatly, ρ_Hz(ω) be APPARENT RESISTIVITY.

In above-mentioned formula (3) and (4), dL, r andBe the device parameter of observation device, according to field source and observation stationPosition coordinate is determined these parameters, observing after vertical magnetic field time series, according to the frequency response of the earth to be measured, vertical magnetic fieldTime series and these device parameters, the APPARENT RESISTIVITY that obtains the earth to be measured by formula (3) and (4) is composed.

In embodiments of the present invention, when receiving electromagnetic field component while being vertical magnetic field time series Hz, with by calculating aboveProcess, the frequency response deformable shown in formula (9) is following formula (13):

$Z_{Hz}\left(\mathrm{\ω}\right)=\frac{P_{CHzs}\left(\mathrm{\ω}\right)}{P_{{\mathrm{CI}}_{AB}s}\left(\mathrm{\ω}\right)}\mathrm{...}\left(13\right)$

Wherein, in formula (13), P_CHzs(ω) be the mutual merit of reference signal SS and vertical magnetic field component time series HzRate spectrum,For the emission current I of reference signal SS and horizontal electric dipole_AB(t) crosspower spectrum.

The vertical magnetic field Hz computing formula (14) being produced by even Earth Surface horizontal electric dipole source:

Wherein, in formula (14), I is emission current, and r is that magnetic field acceptance point is between the two poles of the earth mid point of horizontal electric dipoleDistance,That magnetic field acceptance point is to the line between the two poles of the earth mid point of horizontal electric dipole and the two poles of the earth extended line of horizontal electric dipoleAngle. DL is two die openings of horizontal electric dipole.For even wave number greatly, μ₀It is the magnetic conductance of free spaceRate, i is imaginary unit.

Above-mentioned formula (14) both sides, divided by emission current I, then, with formula (13) correspondent equal, can be obtained to formula(3) the frequency response Z of the earth to be measured shown in_Hz(ω), Z wherein_Hz(ω) be to be followed by observation vertical magnetic field Hz and excitation current IThe earth Frequency response that the identification of ring cross-correlation obtains. By above-mentioned formula (3) is out of shape and can be obtained as formula (4) instituteThe APPARENT RESISTIVITY spectrum of the earth to be measured showing, wherein the APPARENT RESISTIVITY shown in formula (4) need to adopt solution by iterative method.

In embodiments of the present invention, except obtaining by the way the APPARENT RESISTIVITY spectrum of the earth to be measured, all rightTransfer function by identification the earth to be measured is obtained effective resistivity, specifically comprises:

According to the frequency response of the earth to be measured, obtain the transfer function of the earth to be measured, calculate the earth to be measured by transfer functionStep response or impulse response, according to the asymptotic value or peak value moment of impulse response in late period of step response, calculate to be measured largeThe apparent resistivity on ground.

Because the skin depth of the electromagnetic field of different frequency in the earth is different, the APPARENT RESISTIVITY spectrum obtaining is anti-Reflect the change in resistance of different depth, thereby reach the object of electromagnetic sounding.

In embodiments of the present invention, repeating M sequential coding source because adopted excitation signal is contrary is broadband signal, instituteThe apparent resistivity spectrum of a series of frequencies can be provided with the method providing by the embodiment of the present invention simultaneously. In order to improve the complete of acquisitionThe quality of data of district apparent resistivity spectrum, need to transmit and receive the contrary M of the repetition sequential coding source signal in multiple cycles, so canImprove the signal to noise ratio of obtaining APPARENT RESISTIVITY.

In embodiments of the present invention, carry out emission current letter by coding source electromagnetic sounding emission system as shown in Figure 1 FNumber, coding source electromagnetic sounding emission system can be selected output encoder source forcing waveform, can selective exitation frequency band. Excitation waveform comprisesThe contrary M sequence that repeats that register figure place is different, the shift register figure place that produces the contrary M of repetition sequence is preferably 5,6,7,8,9,10,11. Shift register figure place is more, and the contrary repetition M sequence period of generation is longer, and signal band is wider. Produce motivated frequency bands byThe clock frequency of excitation shift register action is definite, and clock frequency is higher, and signal band is higher.

Receive electromagnetic field response signal time series by coding source electromagnetic sounding receiver system as shown in Figure 1 G.Receiver system can gather single track or multiple tracks electric field signal and field signal. Adopt different for the electromagnetic field signal of different frequency bandsSample rate acquisition time sequence, sample rate should have many groups adjustable, adopts higher sample rate sampling for high-frequency band signals, rightAdopt lower sample rate sampling in low band signal. Receiver system is furnished with memory space and the data that can store mass dataTransfer function. Coding source electromagnetic sounding receiver system and coding source electromagnetic sounding emission system can adopt GPS (GlobalPositioningSystem, global positioning system) synchronous or high-precision quartz clock is synchronous.

In embodiments of the present invention, current signal time series by being connected in series high-power sampled electricity in transmission current supply circuitResistance sampling, uses the receiver identical with receiving electromagnetic field, gathers excitation current time series by identical sample rate. In the present inventionIn embodiment, can adopt axial device array observation electric field component, or adopt equatorial array observation electric field component orVertical magnetic field component all can high accuracy, high-resolution obtains the earth APPARENT RESISTIVITY spectrum.

In the time that array is observed, each receiver and receive that the uniformity of electric field or magnetic field sensor can be by instrumental calibrationMode solves. The fixed receiving machine frequency response of bidding is H_s(ω), can remove receiver system self by following formula (15)Impact:

$H\left(\mathrm{\ω}\right)=\left(\frac{P_{Cys}\left(\mathrm{\ω}\right)}{P_{Cus}\left(\mathrm{\ω}\right)}\right)/H_s\left(\mathrm{\ω}\right)\mathrm{...}\left(15\right)$

In order to improve accuracy of observation and quality, acquisition system configuration quality monitoring system, data are processed in real time, in the multicycleElectric current excites down, and accuracy of observation reaches setting requirement side and stops sampling.

In embodiments of the present invention, to the earth input current signal to be measured, gather the electromagnetic field response of the earth output to be measuredSignal time sequence, current signal is against repeating the even-multiple that M sequence and cycle are power frequency period; According to current signal and electromagnetismField response signal time series, the frequency response of obtaining the earth to be measured by Cyclic Cross-Correlation Transform mode; According to the frequency of the earth to be measuredRate response and reception electromagnetic field component, obtain the APPARENT RESISTIVITY of the earth to be measured and compose. The present invention is by the contrary electricity that repeats M sequenceStream signal excitation, adopts Cyclic Cross-Correlation Transform technology to obtain APPARENT RESISTIVITY spectrum, has improved the efficiency of obtaining APPARENT RESISTIVITY,And improved the frequency resolution of the APPARENT RESISTIVITY of obtaining, and owing to adopting the contrary M of repetition of cross-correlation method and current signal orderThe even-multiple that the cycle of row is power frequency period, can effectively suppress power frequency and disturb, and has strengthened antijamming capability.

Embodiment 2

Referring to Fig. 2, the embodiment of the present invention provides a kind of coding source electromagnetic sounding method to obtain the earth APPARENT RESISTIVITY spectrumDevice, this device obtains the earth APPARENT RESISTIVITY spectrum for the coding source electromagnetic sounding method of carrying out above-described embodiment 1 and providingMethod. This device specifically comprises:

Acquisition module 201, for to the earth input current signal to be measured, gathers the electromagnetic field response letter of the earth output to be measuredNumber time series, current signal is the contrary even-multiple that M sequence and cycle are power frequency period that repeats;

The first acquisition module 202, for according to current signal and electromagnetic field response signal time series, mutual by circulatingPass mode is obtained the frequency response of the earth to be measured;

The second acquisition module 203, for according to the frequency response of the earth to be measured and reception electromagnetic field component, obtains to be measured largeThe APPARENT RESISTIVITY spectrum on ground.

Above-mentioned the first acquisition module 202 obtains by Cyclic Cross-Correlation Transform unit, Fourier transformation unit and acquiring unitThe frequency response of the earth to be measured. Cyclic Cross-Correlation Transform unit, for the time series cycle according to current signal and sample rate triggeringSoftware program generating reference signal, circulates electromagnetic field response signal time series and current signal respectively with reference signalCross-correlation, while obtaining cross-correlation corresponding to cross-correlation time series corresponding to electromagnetic field response signal time series and current signalBetween sequence; Fourier transformation unit, for cross-correlation time series and the electric current corresponding to electromagnetic field response signal time seriesThe cross-correlation time series that signal is corresponding is carried out respectively FFT, obtains electromagnetic field response signal seasonal effect in time series mutualThe crosspower spectrum of power spectrum and current signal; Acquiring unit, for according to electromagnetic field response signal seasonal effect in time series crosspower spectrumAnd the crosspower spectrum of current signal, the frequency response of obtaining the earth to be measured.

In the time that reception electromagnetic field component is horizontal component of electric field time series, the second acquisition module 203 obtains unit by firstCalculate APPARENT RESISTIVITY with the first computing unit.

First obtains unit, for according to the frequency response of described the earth to be measured, obtains described to be measured large by formula (1)The impedance spectrum on ground and the relational expression that receives electromagnetic field component and ground resistivity;

The first computing unit, for carrying out the relational expression corresponding to impedance spectrum of described the earth to be measured corresponding to formula (1)Distortion, the APPARENT RESISTIVITY that obtains the described the earth to be measured shown in formula (2) is composed;

$Z_{Ex}\left(\mathrm{\ω}\right)=\frac{\mathrm{\ρ}\left(\mathrm{\ω}\right)dL\·MN}{2{\mathrm{\πr}}^3}{C}_{Ex}\mathrm{...}\left(1\right)$

${\mathrm{\ρ}}_{Ex}\left(\mathrm{\ω}\right)=\frac{2{\mathrm{\πr}}^3\·Z_{Ex}\left(\mathrm{\ω}\right)}{dL\·MN\·C_{Ex}}\mathrm{...}\left(2\right)$

Wherein, in formula (1) and (2), Z_Ex(ω) be the earth impedance, ρ is even resistivity greatly, and ω is frequency,DL is two die openings of horizontal electric dipole, the electrode spacing that MN is collecting electrode, the mid point that r is collecting electrode and horizontal electric dipoleThe two poles of the earth mid point between distance,For the mid point of collecting electrode extremelyThe angle of the line between the two poles of the earth mid point of horizontal electric dipole and the two poles of the earth line of horizontal electric dipole, i is imaginary unit,For even wave number greatly, μ₀For the magnetic conductivity of free space, ρ_Ex(ω) be APPARENT RESISTIVITY.

In above-mentioned formula (1) and (2), dL, MN, r andBe the device parameter of observation device, according to field source and observationPosition coordinate is determined these parameters, is observing after horizontal component of electric field time series, according to the frequency response of the earth to be measured, level electricityField time sequence and these device parameters, the APPARENT RESISTIVITY that obtains the earth to be measured by formula (1) and (2) is composed.

Be vertical magnetic field time series when receiving electromagnetic field component;

Described the second acquisition module 203 comprises:

Second obtains unit, for according to the frequency response of described the earth to be measured, obtains described to be measured large by formula (3)The frequency response on ground and the relational expression that receives electromagnetic field component and ground resistivity;

The second computing unit, for relational expression corresponding to described frequency response corresponding to formula (3) is out of shape, obtainsThe APPARENT RESISTIVITY spectrum of the described the earth to be measured shown in formula (4);

Wherein, in formula (3) and (4), Z_Hz(ω) be frequency response, ρ is even resistivity greatly, and ω is frequency,DL is two die openings of horizontal electric dipole, the distance between the two poles of the earth mid point of the mid point that r is collecting electrode and horizontal electric dipole, μ₀For the magnetic conductivity of free space, i is imaginary unit,For the mid point of collecting electrode is between the two poles of the earth mid point of horizontal electric dipoleThe angle of the two poles of the earth line of line and horizontal electric dipole, $C_{Hz}=1-(1-{\mathrm{ik}}_{1}r-\frac{1}{3}{\left(k_{1}r\right)}^2)\exp \left({\mathrm{ik}}_{1}r\right),k_1^2={\mathrm{i\ω\μ}}_0/\mathrm{\ρ}$ For even wave number greatly, ρ_Hz(ω) be APPARENT RESISTIVITY.

In above-mentioned formula (3) and (4), dL, r andBe the device parameter of observation device, according to field source and observation stationPosition coordinate is determined these ginsengs, is observing after vertical magnetic field time series, during according to the frequency response of the earth to be measured, vertical magnetic fieldBetween sequence and these device parameters, obtain the APPARENT RESISTIVITY spectrum of the earth to be measured by formula (3) and (4).

In embodiments of the present invention, this device can also obtain APPARENT RESISTIVITY by following computing module.

Computing module, for according to the frequency response of described the earth to be measured, obtains the transfer function of described the earth to be measured, byDescribed transfer function is calculated step response or the impulse response of described the earth to be measured, according to the asymptotic value in late period of described step responseOr the peak value moment of described impulse response, calculate the apparent resistivity of described the earth to be measured.

In embodiments of the present invention, to the earth input current signal to be measured, gather the electromagnetic field response of the earth output to be measuredSignal time sequence, current signal is against repeating the even-multiple that M sequence and cycle are power frequency period; According to current signal and electromagnetismField response signal time series, the frequency response of obtaining the earth to be measured by Cyclic Cross-Correlation Transform mode; According to the frequency of the earth to be measuredRate response and reception electromagnetic field component, obtain the APPARENT RESISTIVITY of the earth to be measured and compose. The present invention is by the contrary electricity that repeats M sequenceStream signal excitation, adopts Cyclic Cross-Correlation Transform technology to obtain APPARENT RESISTIVITY spectrum, has improved the efficiency of obtaining APPARENT RESISTIVITY,And improved the frequency resolution of the APPARENT RESISTIVITY of obtaining, and owing to adopting the contrary M of repetition of cross-correlation method and current signal orderThe even-multiple that the cycle of row is power frequency period, can effectively suppress power frequency and disturb, and has strengthened antijamming capability.

It is passable that the coding source electromagnetic sounding method that the embodiment of the present invention provides is obtained the device of the earth APPARENT RESISTIVITY spectrumFor the specific hardware on equipment or be installed on software or the firmware etc. on equipment. Those skilled in the art can be clearlyRecognize, for convenience and simplicity of description, the specific works process of the module of aforementioned description, device and unit, all can referenceCorresponding process in said method embodiment.

In the several embodiment that provide in the application, should be understood that, the apparatus and method that disclose, can pass through otherMode realize. Device embodiment described above is only that schematically for example, the division of described unit, is only oneKind of logic function is divided, and when actual realization, can have other dividing mode, again for example, multiple unit or assembly can in conjunction with orPerson can be integrated into another system, or some features can ignore, or does not carry out. Another point, shown or discussed is mutualBetween coupling or direct-coupling or communication connection can be by some communication interfaces, device or the INDIRECT COUPLING of unit or logicalLetter connects, and can be electrically, machinery or other form.

The described unit as separating component explanation can or can not be also physically to separate, aobvious as unitThe parts that show can be or can not be also physical locations, can be positioned at a place, or also can be distributed to multipleOn NE. Can select according to the actual needs some or all of unit wherein to realize the order of the present embodiment scheme.

In addition, the each functional unit in each embodiment of the present invention can be integrated in a processing unit, also canBe that the independent physics of unit exists, also can be integrated in a unit two or more unit.

If described function realizes and during as production marketing independently or use using the form of SFU software functional unit, canBe stored in a computer read/write memory medium. Based on such understanding, technical scheme of the present invention in essence in other wordsThe part that prior art is contributed or the part of this technical scheme can embody with the form of software product, this meterCalculation machine software product is stored in a storage medium, comprises that some instructions (can be individual in order to make a computer equipmentPeople's computer, server, or the network equipment etc.) carry out all or part of step of method described in each embodiment of the present invention.And aforesaid storage medium comprises: USB flash disk, portable hard drive, read-only storage (ROM, Read-OnlyMemory), arbitrary access are depositedThe various media that can be program code stored such as reservoir (RAM, RandomAccessMemory), magnetic disc or CD.

The above, be only the specific embodiment of the present invention, but protection scope of the present invention is not limited to this, anyBe familiar with those skilled in the art in the technical scope of the present invention's exposure, can expect easily changing or replacing, all should containCover within protection scope of the present invention. Therefore, protection scope of the present invention should be as the criterion with the protection domain of described claim.

Claims (10)

1. coding source electromagnetic sounding method is obtained a method for the earth APPARENT RESISTIVITY spectrum, it is characterized in that described method bagDraw together:

To the earth input current signal to be measured, gather the electromagnetic field response signal time series of described the earth output to be measured, described inCurrent signal is against repeating the even-multiple that M sequence and cycle are power frequency period;

According to described current signal and described electromagnetic field response signal time series, described in obtaining by Cyclic Cross-Correlation Transform mode, treatSurvey the frequency response of the earth;

According to the frequency response of described the earth to be measured and reception electromagnetic field component, obtain the APPARENT RESISTIVITY of described the earth to be measuredSpectrum.

2. method according to claim 1, is characterized in that, described according to described current signal and the response of described electromagnetic fieldSignal time sequence, the frequency response of obtaining described the earth to be measured by Cyclic Cross-Correlation Transform mode, comprising:

Trigger software program generating reference signal according to the time series cycle of described current signal and sample rate, by described electromagnetismField response signal time series and described current signal carry out Cyclic Cross-Correlation Transform with described reference signal respectively, obtain described electromagnetismCorresponding cross-correlation time series and cross-correlation time series corresponding to described current signal of field response signal time series;

To cross-correlation time series corresponding to described electromagnetic field response signal time series and described current signal corresponding mutuallyClose time series and carry out respectively FFT, obtain described electromagnetic field response signal seasonal effect in time series crosspower spectrum and instituteState the crosspower spectrum of current signal;

According to the crosspower spectrum of described electromagnetic field response signal seasonal effect in time series crosspower spectrum and described current signal, described in obtainingThe frequency response of the earth to be measured.

3. method according to claim 1, is characterized in that, described reception electromagnetic field component is horizontal component of electric field time orderRow;

Described according to the frequency response of described the earth to be measured and reception electromagnetic field component, electricity is looked by the whole district that obtains described the earth to be measuredResistance rate spectrum, comprising:

According to the frequency response of described the earth to be measured, obtain the impedance spectrum and reception electromagnetism of described the earth to be measured by formula (1)The relational expression of field component and ground resistivity;

Relational expression corresponding to impedance spectrum to described the earth to be measured corresponding to formula (1) is out of shape, and obtains shown in formula (2)The APPARENT RESISTIVITY spectrum of described the earth to be measured;

$Z_{Ex}\left(\mathrm{\ω}\right)=\frac{\mathrm{\ρ}\left(\mathrm{\ω}\right)dL\·MN}{2{\mathrm{\πr}}^3}{C}_{Ex}...\left(1\right)$

${\mathrm{\ρ}}_{Ex}\left(\mathrm{\ω}\right)=\frac{2{\mathrm{\πr}}^3\·Z_{Ex}\left(\mathrm{\ω}\right)}{dL\·MN\·C_{Ex}}...\left(2\right)$

Wherein, in formula (1) and (2), Z_Ex(ω) be the earth impedance, ρ is even resistivity greatly, and ω is frequency, and dL isTwo die openings of horizontal electric dipole, the electrode spacing that MN is collecting electrode, two of the mid point that r is collecting electrode and horizontal electric dipoleDistance between utmost point mid point, For the mid point of collecting electrode is to level electricityThe angle of the line between the two poles of the earth mid point in even source and the two poles of the earth line of horizontal electric dipole, i is imaginary unit,ForEven wave number greatly, μ₀For the magnetic conductivity of free space, ρ_Ex(ω) be described APPARENT RESISTIVITY.

4. method according to claim 1, is characterized in that, described reception electromagnetic field component is vertical magnetic field time orderRow;

Described according to the frequency response of described the earth to be measured and reception electromagnetic field component, electricity is looked by the whole district that obtains described the earth to be measuredResistance rate spectrum, comprising:

According to the frequency response of described the earth to be measured, obtain the frequency response and reception electricity of described the earth to be measured by formula (3)The relational expression of magnetic-field component and ground resistivity;

Relational expression corresponding to described frequency response that formula (3) is corresponding is out of shape, obtains described to be measured shown in formula (4)The APPARENT RESISTIVITY spectrum of the earth;

Wherein, in formula (3) and (4), Z_Hz(ω) be described frequency response, ρ is even resistivity greatly, and ω is frequency,DL is two die openings of horizontal electric dipole, the distance between the two poles of the earth mid point of the mid point that r is collecting electrode and horizontal electric dipole, μ₀For the magnetic conductivity of free space, i is imaginary unit,For the mid point of collecting electrode is between the two poles of the earth mid point of horizontal electric dipoleThe angle of the two poles of the earth line of line and horizontal electric dipole, $C_{Hz}=1-(1-{\mathrm{ik}}_{1}r-\frac{1}{3}{\left(k_{1}r\right)}^2)\exp \left({\mathrm{ik}}_{1}r\right),k_1^2={\mathrm{i\ω\μ}}_0/\mathrm{\ρ}$ For even wave number greatly, ρ_Hz(ω) be described APPARENT RESISTIVITY.

5. method according to claim 1, is characterized in that, described method also comprises:

According to the frequency response of described the earth to be measured, obtain the transfer function of described the earth to be measured, calculated by described transfer functionThe step response of described the earth to be measured or impulse response, according to the asymptotic value or described impulse response in late period of described step responseIn the peak value moment, calculate the apparent resistivity of described the earth to be measured.

6. coding source electromagnetic sounding method is obtained a device for the earth APPARENT RESISTIVITY spectrum, it is characterized in that described device bagDraw together:

Acquisition module, for to the earth input current signal to be measured, gathers the electromagnetic field response signal of described the earth output to be measuredTime series, described current signal is against repeating the even-multiple that M sequence and cycle are power frequency period;

The first acquisition module, for according to described current signal and described electromagnetic field response signal time series, mutual by circulatingRelevant mode is obtained the frequency response of described the earth to be measured;

The second acquisition module, for according to the frequency response of described the earth to be measured and reception electromagnetic field component, obtains described to be measuredThe APPARENT RESISTIVITY spectrum of the earth.

7. device according to claim 6, is characterized in that, described the first acquisition module comprises:

Cyclic Cross-Correlation Transform unit, for the time series cycle according to described current signal and the generation of sample rate triggering software programReference signal, circulates described electromagnetic field response signal time series and described current signal respectively with described reference signalCross-correlation, obtains described electromagnetic field response signal time series corresponding cross-correlation time series and described current signal correspondingCross-correlation time series;

Fourier transformation unit, for to cross-correlation time series corresponding to described electromagnetic field response signal time series and described inThe cross-correlation time series that current signal is corresponding is carried out respectively FFT, obtains the described electromagnetic field response signal timeThe crosspower spectrum of sequence and the crosspower spectrum of described current signal;

Acquiring unit, for according to the mutual merit of described electromagnetic field response signal seasonal effect in time series crosspower spectrum and described current signalRate spectrum, the frequency response of obtaining described the earth to be measured.

8. device according to claim 6, is characterized in that, described reception electromagnetic field component is horizontal component of electric field time orderRow;

Described the second acquisition module comprises:

First obtain unit, for according to the frequency response of described the earth to be measured, obtains described the earth to be measured by formula (1)Impedance spectrum and the relational expression that receives electromagnetic field component and ground resistivity;

The first computing unit, for the relational expression corresponding to impedance spectrum of described the earth to be measured corresponding to formula (1) is out of shape,Obtain the APPARENT RESISTIVITY spectrum of the described the earth to be measured shown in formula (2);

$Z_{Ex}\left(\mathrm{\ω}\right)=\frac{\mathrm{\ρ}\left(\mathrm{\ω}\right)dL\·MN}{2{\mathrm{\πr}}^3}{C}_{Ex}...\left(1\right)$

${\mathrm{\ρ}}_{Ex}\left(\mathrm{\ω}\right)=\frac{2{\mathrm{\πr}}^3\·Z_{Ex}\left(\mathrm{\ω}\right)}{dL\·MN\·C_{Ex}}...\left(2\right)$

Wherein, in formula (1) and (2), Z_Ex(ω) be the earth impedance, ρ is even resistivity greatly, and ω is frequency, and dL isTwo die openings of horizontal electric dipole, the electrode spacing that MN is collecting electrode, two of the mid point that r is collecting electrode and horizontal electric dipoleDistance between utmost point mid point, For the mid point of collecting electrode is to level electricityThe angle of the line between the two poles of the earth mid point in even source and the two poles of the earth line of horizontal electric dipole, i is imaginary unit,ForEven wave number greatly, μ₀For the magnetic conductivity of free space, ρ_Ex(ω) be described APPARENT RESISTIVITY.

9. device according to claim 6, is characterized in that, described reception electromagnetic field component is vertical magnetic field time orderRow;

Described the second acquisition module comprises:

Second obtain unit, for according to the frequency response of described the earth to be measured, obtains described the earth to be measured by formula (3)Frequency response and the relational expression that receives electromagnetic field component and ground resistivity;

The second computing unit, for relational expression corresponding to described frequency response corresponding to formula (3) is out of shape, obtains formula(4) the APPARENT RESISTIVITY spectrum of the described the earth to be measured shown in;

Wherein, in formula (3) and (4), Z_Hz(ω) be described frequency response, ρ is even resistivity greatly, and ω is frequency,DL is two die openings of horizontal electric dipole, the distance between the two poles of the earth mid point of the mid point that r is collecting electrode and horizontal electric dipole, μ₀For the magnetic conductivity of free space, i is imaginary unit,For the mid point of collecting electrode is between the two poles of the earth mid point of horizontal electric dipoleThe angle of the two poles of the earth line of line and horizontal electric dipole, $C_{Hz}=1-(1-{\mathrm{ik}}_{1}r-\frac{1}{3}{\left(k_{1}r\right)}^2)\exp \left({\mathrm{ik}}_{1}r\right),k_1^2={\mathrm{i\ω\μ}}_0/\mathrm{\ρ}$ For even wave number greatly, ρ_Hz(ω) be described APPARENT RESISTIVITY.

10. device according to claim 6, is characterized in that, described device also comprises:

Computing module, for according to the frequency response of described the earth to be measured, obtains the transfer function of described the earth to be measured, by describedTransfer function is calculated step response or the impulse response of described the earth to be measured, according to the asymptotic value or institute in late period of described step responseState the peak value moment of impulse response, calculate the apparent resistivity of described the earth to be measured.